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Rails where condition using NOT NIL
...S NOT NULL
Note that this syntax reports a deprecation (it talks about a string SQL snippet, but I guess the hash condition is changed to string in the parser?), so be sure to add the references to the end:
Foo.includes(:bar).where.not(bars: {id: nil}).references(:bar)
DEPRECATION WARNING: I...
What is a NullPointerException, and how do I fix it?
...your code can help avoid null pointer exception. eg when checking an input string with a constant string you should start with the constant string like here: if ("SomeString".equals(inputString)) {} //even if inputString is null no exception is thrown. So there are a bunch of things that you can do ...
If vs. Switch Speed
...ector to look at the code produced, you will see that for huge switches on strings, the compiler will actually generate code that uses a hash table to dispatch these. The hash table uses the strings as keys and delegates to the case codes as values.
This has asymptotic better runtime than lots of c...
Differences between INDEX, PRIMARY, UNIQUE, FULLTEXT in MySQL?
...b (In MySQL 5.6.4 and up) and Myisam Engines
You can only use FULLTEXT on CHAR, VARCHAR and TEXT column types
FULLTEXT index involves a LOT more than just creating an index. There's a bunch of system tables created, a completely separate caching system and some specific rules and optimizations app...
How to parse freeform street/postal address out of text, and into components
...orce'? Breaking up text into all possible combinations of possible address strings and comparing each one against a database of addresses is not practical and will take way more time to provide an answer than this system does. Openaddresses are one of the data sources for building a 'training set' o...
Changing every value in a hash in Ruby
...
If you want the actual strings themselves to mutate in place (possibly and desirably affecting other references to the same string objects):
# Two ways to achieve the same result (any Ruby version)
my_hash.each{ |_,str| str.gsub! /^|$/, '%' }
my_h...
Serializing object that contains cyclic object value
...
Use the second parameter of stringify, the replacer function, to exclude already serialized objects:
var seen = [];
JSON.stringify(obj, function(key, val) {
if (val != null && typeof val == "object") {
if (seen.indexOf(val) >= 0)...
Get Android .apk file VersionName or VersionCode WITHOUT installing apk
...
final PackageManager pm = getPackageManager();
String apkName = "example.apk";
String fullPath = Environment.getExternalStorageDirectory() + "/" + apkName;
PackageInfo info = pm.getPackageArchiveInfo(fullPath, 0);
Toast.makeText(this, "VersionCode : " + info.versi...
What are the “standard unambiguous date” formats for string-to-date conversion in R?
...
This is documented behavior. From ?as.Date:
format: A character string. If not specified, it will try
'"%Y-%m-%d"' then '"%Y/%m/%d"' on the first non-'NA' element,
and give an error if neither works.
as.Date("01 Jan 2000") yields an error because the format isn'...
What is the purpose of backbone.js?
... and are generally bad form. Data attributes stored in the DOM can only be strings, you will have to parse them in and out again. It's difficult to store things like arrays, dates or objects, and to parse your data in a structured form.
Data attributes look like this:
<p data-username="derek" d...